Stereo image capture and processing

ABSTRACT

Apparatus and systems, as well as methods and articles, may operate to capture a portion of an omniscopic or omni-stereo image using one or more image capture media. The media may be located substantially perpendicular to a converging ray originating at a viewpoint on an inter-ocular circle and having a convergence angle between zero and ninety degrees from a parallel viewpoint baseline position that includes a non-converging ray originating at the viewpoint. The media may also be located so as to be substantially perpendicular to a non-converging ray originating at a first viewpoint at a first endpoint of a diameter defining an inter-ocular circle, wherein the origin of the non-converging ray gravitates toward the center of the inter-ocular circle as spherical imagery is acquired.

RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.13/008,021 filed Jan. 18, 2011 (which issued as U.S. Pat. No. 8,334,895on Dec. 18, 2012, titled “Image Capture and Processing using ConvergingRays”), which is a divisional of U.S. patent application Ser. No.11/128,845 filed May 13, 2005, titled “Image Capture and Processing”(which issued as U.S. Pat. No. 7,872,665 on Jan. 18, 2011), each ofwhich is incorporated herein by reference in its entirety.

This disclosure is related to U.S. patent application Ser. No.11/128,712, titled “Image Processing and Display,” filed on May 13, 2005(which issued as U.S. Pat. No. 7,656,403 on Feb. 2, 2010), assigned tothe assignee of the embodiments disclosed herein, Micoy Corporation, andincorporated herein by reference in its entirety.

TECHNICAL FIELD

Various embodiments described herein relate to image processinggenerally, including apparatus, systems, and methods used to capture,process, and display image information.

BACKGROUND INFORMATION

Omni-stereo imaging research may involve the capture and display ofstereoscopic (stereo) three-dimensional imagery for substantially all ofan environment (omni), including one or more spherical images. Manytechniques have been developed for capturing omni-directional monoscopicimagery of an environment using wide-angle lenses, mirrors, and variousimage mosaicing techniques. Similarly, many techniques have beendeveloped for capturing stereoscopic imagery. There are even sometechniques that can be used to capture stereoscopic omni-directional(omni-stereo) imagery.

Early attempts made use of two monoscopic omni-directional camerasvertically displaced along a common axis. By comparing the imagery fromboth cameras, depth information could be extracted from the surroundingscene. However, human eyes are horizontally displaced, rather thanvertically, so the omni-stereo imagery produced by the vertical cameraarrangement is inappropriate for human stereo perception.

Some techniques rely on specially constructed spiral mirrors and/orlenses. While these devices theoretically are capable of capturingomni-stereo imagery in real time, they are cylindrical, rather thanspherical, in nature. Thus, they may capture 360° of imagery in thehorizontal direction, but are more limited in the vertical direction,and usually unable to capture more than 90° of vertical imagery. Whilesome of these theoretical formulations have been extrapolated into aspherical context, the resulting spherical omnivergent images aredesigned for automated stereo reconstruction operations, rather thanhuman stereoscopic viewing.

Another approach, using a center-strip omnivergent sensor, can beapplied more directly to human stereoscopic viewing. This sensorcaptures a succession of circular imaging sweeps and merges them into aunified panoramic image. Thus, a camera may be placed at successivepositions around a circle, and at each position, the camera can berotated 360° about its central axis (coinciding with a radius of thecircle), so as to capture a full circle of image data. This processresults in a unified panoramic image containing both forward andbackward tangent rays. Decomposing the image into separate forward andbackward tangent ray images permits stereoscopic viewing when one imageis shown to each eye of the viewer. However, this approach also fails tocapture some of the image data.

Spherical imagery is usually displayed to a human viewer by mappingimages onto a spherical surface that surrounds the viewer. The viewercan then change the viewing direction interactively to explore theenvironment. However, when images provided by a center-strip omnivergentsensor are viewed in this manner, it becomes apparent that thetangential camera path results in a failure to capture the areas of thesurrounding environment corresponding to the top and bottom apexes ofthe spherical field of view—that is, some areas near the apexes of thesphere are simply missing. Thus, omniscopic and stereoscopic viewing ofsuch imagery is flawed at the apexes (e.g., above the viewer's head, andat the viewer's feet). The use of toroidal topology for panoramicimagery also fails to solve such apex viewing flaws.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-1F illustrate converging ray image capture apparatus accordingto various embodiments of the invention.

FIGS. 2A-2B illustrate top and perspective views, respectively, ofconverging ray camera sweep paths according to various embodiments ofthe invention.

FIGS. 3A-3B illustrate top and perspective views, respectively, oftwist-corrected converging ray camera sweep paths according to variousembodiments of the invention.

FIGS. 4A-4D illustrate gravitating ray image capture apparatus accordingto various embodiments of the invention.

FIGS. 5A-5B illustrate top and perspective views, respectively, ofgravitating ray camera sweep paths according to various embodiments ofthe invention.

FIG. 6 is a block diagram illustrating apparatus and systems accordingto various embodiments of the invention.

FIGS. 7A-7B are flow diagrams illustrating several methods according tovarious embodiments of the invention.

FIG. 8 is a block diagram of an article according to various embodimentsof the invention.

DETAILED DESCRIPTION

The distortion of images discussed previously is caused by collectingapex image data from a multitude of different viewing positions. Eventhough all of the image capture rays for a given apex may be oriented inthe same direction (directly up or down), their origins are displacedfrom one another around the specified inter-ocular circle. As such, eachapex capture ray is pointing toward a slightly different location in thesurrounding environment.

Various embodiments disclosed herein may address the challenge ofre-orienting apex capture rays by changing the manner in which imagesare captured. Thus, some embodiments disclosed herein make use ofcameras and other image capture media oriented to take advantage ofconverging capture rays. Others use capture media located so as to makeuse of capture rays having origins that gravitate toward the center ofthe inter-ocular circle. It should be noted that the term “camera” and“image capture medium” are used interchangeably throughout the followingdiscussion, and both terms refer to devices that can be used to captureimage information from the surrounding environment, converting lightenergy to electrical signals, such as CCDs (charge-coupled devices)arrays, CMOS (complementary metal-oxide semiconductor) sensor arrays,etc. In the case of embodiments where images are generated by computer,rather than captured from the surrounding physical environment, imagecapture media may comprise one or more registers, buffers, or othermemories to store image pixel information. In such embodiments, theremay be no need to transfer image information to a separate image storagemedium.

FIGS. 1A-1F illustrate converging ray image capture apparatus 100according to various embodiments of the invention. These figuresdemonstrate that spherical images 112 may be captured by locating imagecapture media 114′, 114″ so that apex capture rays (converging rays118′, 118″) point to the same location in the surrounding environment.Thus, as the media 114′, 114″ are swept along a variety of paths tocapture the spherical image 112, the path of each medium 114′, 114″ maybe altered so that the converging rays 118′, 118″ (substantiallyperpendicular to the image capture media 114′, 114″ and originating attwo viewpoints 122, 126 on an inter-ocular circle 130) ultimatelyconverge at a convergence point 134 directly above or below theapplicable apex 138. Thus, in FIG. 1A, once the location of aconvergence point 134 is determined, the associated convergence angle142′, 142″ may be found for the desired apex 138.

FIG. 1B illustrates the parallel viewpoint baseline position 146 (e.g.yaw=0 and pitch=0) that includes non-converging rays 144′, 144″originating at the first viewpoint 122 and the second viewpoint 126.

In FIG. 1C, convergence adjustment is demonstrated by rotating eachconvergence ray 118′, 118″ by the desired convergence angle 142′, 142″about the ray origin 122, 126. It should be noted that in manyembodiments, as will be discussed in further detail below, theconvergence rays 118′, 118″ may be rotated continuously, or inincrements (e.g., by a portion of the convergence angle 142′, 142″)throughout spherical image capture operations, such that the convergencerays 118′, 118″ may be characterized by a convergence angle 142′, 142″near zero degrees at the equator of the sphere (pitch=0 degrees), thefull convergence angle at the apex of the sphere (pitch=90 degrees), andsomewhere in between at other pitch angles.

Thus, camera sweep operations may be initiated by using a first imagecapture medium 114′ (located substantially perpendicular to a convergingray 118′ originating at a first viewpoint 122 on the inter-ocular circle130) having a convergence angle 142′ between zero and ninety degreesfrom a parallel viewpoint baseline position 146′. In this manner,spherical image data, such as a triangular portion 150 of anomni-stereoscopic image 112, may be acquired.

In FIG. 1D it can be seen that pitch adjustments during camera sweepoperations can be made to the capture media 114′, 114″ by rotating eachconverging ray 118′, 118″ by the desired pitch angle 152′, 152″ aboutthe Z-axis. In FIG. 1E it can be seen that yaw adjustments during camerasweep operations can be made to the capture media 114′, 114″ by rotatingeach converging ray 118′, 118″ by the desired yaw angle 154′, 154″ aboutthe Y-axis.

In some instances, particularly when the apex convergence point 134 isextremely close to the image capture device (e.g., capture media 114′,114″), some twisting of the image at the apex may be visible upondisplay of the captured image data. Compensation for the twisting effectcan be made by further yaw correction to the camera sweep paths. Thus,in FIG. 1F it can be seen that twist adjustments during camera sweepoperations can be made to the capture media 114′, 114″ by rotating eachconverging ray 118′, 118″ by the desired twist angle 156′, 156″ aboutthe y-axis (e.g., the twist angle may be approximately equal to theconvergence angle 142′, 142″ then in effect, or some selected portionthereof). It should be noted that the twist correction may be made inthe opposite direction to the orientation yaw angle 152′, 152″ (e.g.,the twist correction may be in opposite directions for each eye, so forone eye, the twist correction is in the same direction as the yawcorrection, and for the other eye, it is in the opposite direction,thus, the capture medium for one eye may have a positive twistcorrection applied, and the capture medium for the other eye may have anegative twist correction applied). Thus, while yaw and pitchadjustments that serve to orient the image capture media 114′, 114″properly for spherical image capture tend to push the converging rays118′, 118″ toward convergence, twist correction tends to move themback—away from convergence. However, the net effect is typically anultimate orientation yaw angle that is not zero.

Since the convergence technique maintains apex capture ray origins alongthe specified inter-ocular circle, accurate stereoscopic separation canbe maintained throughout the resulting panorama. When viewing thepanoramic images stereoscopically, the effect achieved may includeparallel eye orientation at the sphere's equator, with slowly convergingeye orientation as the apexes of the sphere are approached. Suchconvergence is unobtrusive to the viewer because a similar effect occursnaturally when a human being focuses their vision on a particularobject. The capture ray convergence technique operates most effectivelyto provide a substantially seamless panorama if the converging capturerays converge to a certain point in the surrounding space, which istypically the closest object surface point that lies directly above orbelow the appropriate apex.

FIGS. 2A-2B illustrate top and perspective views, respectively, ofconverging ray camera sweep paths 258 according to various embodimentsof the invention. Thus, the camera positions (or capture mediapositions) may begin at a parallel baseline position (see FIG. 1B), witha convergence angle 142′, 142″ (see FIG. 1C) of about zero degrees (e.g,greater than zero degrees), and then the convergence angle 142′, 142″may be varied according to some formula from about zero degrees (e.g.,greater than zero degrees) to an ultimate angle that results inintersection at the convergence point 134 (see FIG. 1A). Thisconvergence operation can be performed as the cameras are swept througha series of pitch, yaw, and twist orientations (see FIGS. 1C-1F) whilespherical imagery 112 is captured. Changes made to the convergence angle142′, 142″ during spherical image capture operations may be accomplishedaccording to simple linear interpolation or using more complexmathematical models (e.g. quadratic, logarithmic, etc). The convergenceangle 142′, 142″ may thus be adjusted across the entire 90° camerainclination sweep approaching the apex 238, as shown in FIGS. 2A and 2B,or across a smaller section of the sweep, as desired. The same capturemedium 114′, physically moving along a sweep path 260, or a plurality ofstationary media 114′, 114″, located along the sweep path 260, or somecombination of these, may be used to acquire spherical image data duringsweep operations.

FIGS. 3A-3B illustrate top and perspective views, respectively, oftwist-corrected converging ray camera sweep paths 362 according tovarious embodiments of the invention. As noted previously when theconvergence point is very close to the image capture media, sometwisting of the image data at the apex may be visible upon display.Compensation for the twisting effect may be accomplished usingadditional yaw correction (see FIG. 1F), and FIGS. 3A and 3B illustrateone possible set of camera sweep paths 362 after yaw correction tocompensate for the twist effect has been applied.

The capture ray convergence technique operates well when accurateinformation about the surrounding scene is available, so that variouscapture ray orientations (effected by the capture media location) may beproperly implemented. Thus, the convergence approach lends itself to usein computer graphics environments, where the convergence information isreadily available. However, convergence operations may be less usefulwith respect to the use of physical image capture devices because it canbe difficult to create a device that adjusts to constantly varying apexconvergence points. The resulting spherical imagery may exhibitundesirable apex distortion whenever the properties of the surroundingenvironment conflict with the chosen convergence point.

As mentioned briefly above, the gravitation technique may also be usedto capture spherical imagery. Instead of moving the capture rayorientations toward convergence, this technique involves the gravitationor movement of capture ray origins (i.e., gravitating rays) from theinter-ocular circle diameter endpoints toward the center of theinter-ocular circle as the capture media sweep out their imaging capturepaths.

FIGS. 4A-4D illustrate gravitating ray image capture apparatus 400according to various embodiments of the invention. FIG. 4A illustratesthe parallel viewpoint initial baseline position 446 (e.g. yaw=0 andpitch=0) that includes non-converging rays 444′, 444″ originating at thefirst viewpoint 422 and the second viewpoint 426.

In FIG. 4B it can be seen that pitch adjustments during camera sweepoperations can be made to the capture media 414′, 414″ by rotating eachgravitating capture ray 464′, 464″ by the desired pitch angle 452′, 452″about the Z-axis. In FIG. 4C it can be seen that yaw adjustments duringcamera sweep operations can be made to the capture media 414′, 414″ byrotating each gravitating capture ray 464′, 464″ by the desired yawangle 454′, 454″ about the Y-axis.

In FIG. 4D, it is shown that gravitating capture ray 464′, 464″ origin466′, 466″ adjustment may be accomplished by moving the capture media414′, 414″ (and thus, the origins 466′, 466″ of the gravitating capturerays 464′, 464″) away from the first and second viewpoints 422, 426toward the center 468 of the inter-ocular circle 430 along the diameterD by some desired inter-ocular distance portion 470′, 470″.

Thus, spherical images may be acquired by capturing a first portion ofan image, such as a monoscopic image, a stereoscopic image, or anomni-stereoscopic image, using an image capture medium 414′ oriented soas to be substantially perpendicular to a non-converging ray 444′originating at a first viewpoint 422 coinciding with a first endpoint ofa diameter D defining an inter-ocular circle 430, and capturing a secondportion of the spherical image using the same image capture medium 414′(or another medium 414′) substantially perpendicular to a non-convergingray 444′ originating at a first point 466′ of the diameter D between thefirst endpoint 422 and the center 468 of the inter-ocular circle 430.

Thus, as is the case with the convergence technique, the gravitationaltechnique can make use of the same capture medium, physically movingalong a sweep path, or a plurality of stationary media, located alongthe sweep path, or some combination of these, to acquire image data. Inthe case of implementing either convergence or gravitation sphericalimage capture techniques, it should be noted that image capture mediapitch and yaw values may be used help to locate the acquisition planesof the image capture media in space. That is, spherical images maycomprise image information that is associated with a distinct set ofrays corresponding to a series of yaw (−180° to 180°) and pitch values(−90° to 90°). This information can be used to locate and orient (i.e.,“point”) the image capture media during capture operations, or whenrecorded along with acquired image data, to determine where the imagecapture media were located at the time of image capture activities.

FIGS. 5A-5B illustrate top and perspective views, respectively, ofgravitating ray camera sweep paths 570 according to various embodimentsof the invention. As is the case with convergence, gravitation may alsobe performed according to a simple linear interpolation or using morecomplex mathematical models (e.g. quadratic, logarithmic, etc).Gravitation can be performed across the entire 90° camera inclinationsweep approaching the apex 538, or across a smaller section of thesweep. For example, FIGS. 5A and 5B illustrate top and perspectiveviews, respectively, of camera sweep paths 570 associated with linearlygravitating capture ray origins towards the center of the inter-ocularcircle after the inclination has reached 60°. Gradual gravitation of thecapture ray origin may operate to more effectively fill in missing apeximagery in a substantially seamless fashion than other techniques.

It should be noted that in some embodiments, use of the gravitationtechnique may result in degraded stereoscopy at the spherical apexes.For example, at the apex point, the capture ray origins may no longer bepositioned along the inter-ocular circle. If this is the case, the leftand right eye rays at that position may be identical, producing nostereoscopic effect. The precise pattern of the stereoscopic degradationdepends on the mathematical model that defines the capture ray origindegradation. Using the sweep pattern of FIGS. 5A and 5B as an example,the desired stereoscopic separation can be maintained until 60°inclination (e.g., at a pitch position=±60 degrees with respect to theequator of the spherical image) has been reached, after which thestereoscopic separation will diminish linearly towards the apex point.For many applications, this type of stereoscopic degradation isacceptable, particularly when compared to the apex distortions apparentwith previously available methods.

Since the gravitation technique permits the apex rays to converge to thesame origins and orientations, imagery may be more consistently acquiredas changes occur in the surrounding environment. Parallax distortionsmay be reduced or eliminated. Thus, the gravitation technique may beuseful in computer graphics environments, as well as in theimplementation of physical image capture devices.

To simplify viewing, the acquired images may be stored in anequirectangular image format, even though the image data formulation isnot strictly equirectangular in nature. For example, if theequirectangular image format stores an entire sphere's worth of imagedata according to an angular positioning scheme, then each image pixelcoordinate (x, y) may have a corresponding spherical angular coordinate(yaw, pitch). The horizontal image coordinate may correspond to a yawposition, and the vertical image coordinate may correspond to a pitchposition, for example. Thus, each eye's image may be stored in the sameequirectangular format such that pixel (x,y) in each eye's imagecorresponds to what each eye should see when looking in that direction.The pitch, yaw coordinates may be associated with a particular viewingor “viewer's head” orientation.

Image processing and storage efficiency for spherical image formats maybe improved if image data is captured across the spherical surface in amore evenly distributed fashion. For example, a number of approaches tosubdividing spheres may begin with one of the platonic solids, includingthose polyhedra having faces with equal area, equal edges, and equalangles. Examples include tetrahedrons, hexahedrons, octahedrons,dodecahedrons, and icosahedrons. Various mathematical techniques, knownto those of skill in the art, may be used to generate substantiallyuniformly tesellated spherical surfaces based on these polyhedra. Anysuch representation may be used to implement the techniques describedherein.

In some embodiments, a spherical surface may be divided intosubstantially equally tessellated polygons, such as triangles. The imagedata from a pair of triangles may subsequently be combined and stored ina substantially rectangular format in computer memory. A “triangle”,“triangular image”, or “triangle image” may refer to image data includedin a triangular portion of a substantially uniformly tessellatedspherical surface, such as an omniscopic spherical image. A “rectangle”,“rectangular image”, or “rectangle image” may comprise a combination oftwo triangle images. The triangular images may both be taken from asingle omniscopic image set, or as a stereo pair: one from a left eyeomniscopic spherical image, and one from a right eye omniscopicspherical image, as part of an omni-stereo image set.

It should be noted that the image data included in the rectangularimages does not necessarily have to be stored as a “physical rectangle”or rectangular matrix in memory, although that is certainly an option.Rather, “storing a pair of triangles as a convex quadrilateral” can meanthat data from the pair of triangles is combined in some fashion, andthen stored as a unitary combination of data, accessible as a unit ofdata that may be used to reproduce the image information associated withthat particular pair of triangles. Thus, the image data from the pair oftriangles may be interleaved, compressed, intermingled, or re-arrangedin a number of ways to form a unit that can be stored, accessed, andprocessed as a unified whole.

FIG. 6 is a block diagram illustrating apparatus 600, 660 and systems670 according to various embodiments of the invention, which may operatein the manner described above. Both the convergence and gravitationtechniques may be implemented using a single (or multiple) motorcontrolled or otherwise movable capture media 614′, 614″, as well as aplurality of stationary image capture media 614′, 614″ to capturespherical omniscopic and omni-stereo still images 612. Multiple imagesmay be captured, and then displayed in sequence to create movingomniscopic and omni-stereo movies.

The apparatus 660 may include image storage media 664, such assemiconductor memory, or magnetic/optical disks, or combinations ofthese, to store portions 672 of a spherical image 612 as a pair oftriangles 676 included in a convex quadrilateral 678. In someembodiments, such as a camera, including a video camera, the apparatus660 may include one or more image capture media 614′, 614″ to capture asubset of the portion 672 including at least one of the pair oftriangles 676. As noted previously, image capture media 614′, 614″ mayinclude photosensitive solid state devices, such as CMOS sensors, andCCDs, among others.

It should be noted that the spherical image 612 may comprise amonoscopic spherical image or a stereoscopic spherical (e.g.,omni-stereo) image. In the case of a monoscopic spherical image 612, thepair of triangles 676 may be adjacent each other in a substantiallyuniformly tessellated portion of the spherical image 612. Someembodiments the apparatus 660 may include a processor 684 to controlrepetitive acquisition of other portions 686 of the spherical image 612and storage of the other portions 686 in the image storage medium 664.

Thus, referring now to FIGS. 1A-1F and FIG. 6, it can be seen that insome embodiments, an apparatus 100, 660 may include a first imagecapture medium 114′, 614′ to capture a first portion 672 of a sphericalimage 612. The first image capture medium 114′, 614′ may be located soas to be substantially perpendicular to a converging ray 118′originating at a first viewpoint 122, 622 on an inter-ocular circle 130,630, with a convergence angle 142′ between zero and ninety degrees froma parallel viewpoint baseline position 146 that includes anon-converging ray 144′ originating at the first viewpoint 122, 622.See, for example, FIGS. 1B and 1C. The media 114′, 114″ may be moved tothe orientation described, or be fixed at that orientation. Theapparatus 100, 660 may also include a second image capture medium 114″located at a second viewpoint 126, 626 on the inter-ocular circle 130,630 to capture a second portion 686 of the spherical image.

The apparatus 100, 660 may include an image storage medium 664 to storea subset of the first portion 672 and a subset of the second portion 686as a pair of triangles 676, perhaps included in a convex quadrilateral678. The pair of triangles 676 may be included in a plurality oftriangles 688 forming a substantially uniformly tessellated portion ofthe spherical image 612, and may, for stereoscopic applications, includea first triangle 680 associated with a left eye view (e.g., stored as asubset of portion 672), and a second triangle 682 associated with aright eye view (e.g., stored as a subset of portion 686). In monoscopicapplications, the pair of triangles 676 may be located adjacent eachother in the substantially uniformly tessellated portion of thespherical image 612.

As has been made apparent in FIGS. 1A-1F, one or more image capturemedia 114′, 114″, 614′, 614″ may be oriented so as to be substantiallyperpendicular to a converging ray 118′, 118″ originating at the secondviewpoint 126, 626 and having a convergence angle 142″ between zero andninety degrees from a parallel viewpoint baseline position 146 thatincludes a non-converging ray 144″ originating at the second viewpoint126, 626.

Various convergence angles 142′, 142″ may be achieved. For example, insome embodiments, convergence angle 142′ may be substantially equal toconvergence angle 142″. In some embodiments, convergence angle 142′ maybe substantially unequal to convergence angle 142″. In some embodiments,the convergence angles 142′, 142″ may be substantially equal for a firstportion of a camera sweep operation, and substantially unequal for asecond portion of the camera sweep or spherical image capture operation.It should be noted that a “camera sweep operation” may includephysically moving image capture media 614′, 614″ in space, or acquiringimage data from a plurality of stationary image capture media 614′,614″, such as via electronic multiplexing, where a multiplexer or someother switching arrangement controlled by the processor 684 influencesthe order of image acquisition.

Thus, in some embodiments, the apparatus 100, 660 may include aplurality of additional image capture media 614′, 614″ located along asubstantially circular path (e.g., the inter-ocular circle 630, or pathssimilar to or identical to the sweep paths 258, 362, and 570 of FIGS. 2,3, and 5, respectively) wherein the plurality of additional imagecapture media 614′, 614″ includes a corresponding plurality oforientations, ranging from substantially perpendicular to thenon-converging rays 144′, 144″ to substantially perpendicular to theconverging rays 118′, 118″. The convergence angle 142′, 142″ may beapproximately determined by a convergence point 134 located in a planeincluding the converging ray 118′ (originating at the first viewpoint122) and a mirror image of the converging ray 118″ that intersects theconverging ray 118′ and originates at the second viewpoint 126.

As has been noted, convergence angles 142′, 142″ may range between 0 and90 degrees. In some embodiments, the convergence angles 142′, 142″ mayrange between 1 and 89 degrees. In some embodiments, the convergenceangles 142′, 142″ may range between 1 and 85 degrees. In someembodiments, the convergence angles 142′, 142″ may range between 5 and85 degrees.

Referring now to FIGS. 4A-4D and 6, it can be seen that in someembodiments, a gravitation apparatus 400, 600 may include a first imagecapture medium 414′, 614′ to capture a first portion 672 of a sphericalimage 612, wherein the first image capture medium 414′, 614′ issubstantially perpendicular to a non-converging ray 444′ originating ata first viewpoint 422, 622 at the first endpoint of a diameter Ddefining an inter-ocular circle 430, 630. The apparatus 400, 600 mayinclude a second image capture medium 414′″ to capture a second portion686 of the spherical image 612, wherein the second image capture medium414′″ is substantially perpendicular to a non-converging ray 464′originating on a first point 466′ of the diameter D between the firstendpoint 422, 622 and the center 468 of the inter-ocular circle 430,630. The spherical image 612 may comprise an omni-stereoscopic image.

In some embodiments, the apparatus 600 may include multiple imagecapture media, such as a third image capture medium 414″, 614″ tocapture a third portion 687 of the spherical image 612, wherein thethird image capture medium 414″ is substantially perpendicular to anon-converging ray 444″ originating at a second viewpoint 426, 626 at asecond endpoint of the diameter D defining the inter-ocular circle 430,630. The apparatus 600 may also include an image storage medium 664 tostore a subset of the first portion 672 and a subset of the secondportion 686 as a pair of triangles 676 included in a convexquadrilateral 678.

Other embodiments may be realized. For example, a system 670 may includeone or more apparatus 100, 400, 600, 660, described previously. Thesystem 670 may also include one or more lenses 690 (perhaps divided intomultiple lenses 690′, 690″) to focus the first portion 672 of thespherical image 612 on the first image capture medium 614′, and one ormore lenses 690 (may be the same lens 690, or one of the divided lenses690′, 690″) to focus the second portion 686 of the spherical image 612on the second image capture medium 614″. The lens 690 may include aplurality of facets 692 to focus on corresponding groups of pixels 694forming a portion of the image capture media 614′, 614″. Thecorresponding groups of pixels 694 may be defined by N×N pixel arraysfor N comprising a positive integer (e.g., 1×1, 2×2, 3×3, etc.).

In embodiments of a system 670 that operates via gravitation, the system670 may include a plurality of additional image capture media 614′″located along a substantially circular path 630, wherein the pluralityof additional image capture media include a corresponding plurality oforientations, ranging between the first viewpoint 422, 622 and thesecond viewpoint 426, 626 along the diameter D of the inter-ocularcircle 430, 630.

In some embodiments, the system 670 may include a viewfinder 696 to viewa subset of the first portion 672 and/or a subset of the second portion686. For example, if the system 670 includes a movie camera, theviewfinder 696 may comprise a monoscopic or stereoscopic viewfinder toview a subset of portions of the spherical image.

The apparatus 100, 400, 600, 660; spherical image 112, 612; imagecapture media 114, 114′, 114″, 414′, 414″, 414′, 614′, 614″; convergingrays 118, 118′, 118″; viewpoints 122, 126, 422, 426, 622, 626;inter-ocular circles 130, 430, 630; convergence point 134; apexes 138,238, 338, 538; convergence angles 142′, 142″; baseline positions 146,446; non-converging rays 144′, 144″, 444′, 444″; image portions 150,672, 686, 687; pitch angles 152′, 152″, 452′, 452″; yaw angles 154′,154″, 454′, 454″; twist angles 156′, 156″; sweep paths 258, 260, 362,570; gravitating capture rays 464′, 464″; origins 466′, 466″; center468; inter-ocular distance portions 470′, 470″; storage media 664;systems 670; triangles 676; convex quadrilateral 678; processor 684;triangles 688; lenses 690, 690′, 690″; facets 692; groups of pixels 694;viewfinder 696; and diameter D may all be characterized as “modules”herein.

Such modules may include hardware circuitry, processors, memorycircuits, software program modules and objects, firmware, and/orcombinations thereof, as desired by the architect of the apparatus 100,400, 660 and systems 670, and as appropriate for particularimplementations of various embodiments. For example, such modules may beincluded in a system operation simulation package, such as a softwareelectrical signal simulation package, a power usage simulation package,an image processing package; a movie display package; a power/heatdissipation simulation package, a signal transmission-receptionsimulation package, and/or a combination of software and hardware usedto simulate the operation of various potential embodiments.

It should also be understood that the apparatus and systems of variousembodiments can be used in applications other than acquisition,processing, and display of omni-stereo images, and thus, variousembodiments are not to be so limited. The illustrations of apparatus100, 400, 660 and systems 670 are intended to provide a generalunderstanding of the structure of various embodiments, and they are notintended to serve as a complete description of all the elements andfeatures of apparatus and systems that might make use of the structuresdescribed herein.

Applications that may include the novel apparatus and systems of variousembodiments include electronic circuitry used in high-speed computers,communication and signal processing circuitry, modems, processormodules, embedded processors, data switches, and application-specificmodules, including multilayer, multi-chip modules. Such apparatus andsystems may further be included as sub-components within a variety ofelectronic systems, such as televisions, cellular telephones, personalcomputers, workstations, radios, video players, cameras, projectors,vehicles, and others. Some embodiments include a number of methods.

For example, FIGS. 7A-7B are flow diagrams illustrating several methodsaccording to various embodiments of the invention. Thus, a method 711may (optionally) begin at block 721 with locating a convergence point atthe surface of an object visible to first and second viewpoints, perhapslocated on an inter-ocular circle (e.g., to a left and right eye, forexample). The method 711 may continue at block 725 with determining aconvergence angle by locating the convergence point in a plane includinga converging ray and a mirror image of the converging ray thatintersects the converging ray and originates at the second viewpoint onan inter-ocular circle.

In some embodiments, the method 711 at block 729 includes moving imagecapture media, or locating a plurality of capture media, so as toproperly orient the media for image capture. For example, the media maybe moved or located so that image capture rays originating at selectedviewpoints intersect at a selected convergence point as the media aremanipulated (e.g., physically and/or electronically) to capturespherical imagery. Thus, the method 711 at block 729 may includesweeping an image capture medium about a substantially circular path;and moving the image capture medium from an orientation substantiallyperpendicular to a non-converging ray to substantially perpendicular toa converging ray, as shown and described with respect to FIGS. 1A-1F.

In some embodiments, a full pitch angle sweep may be accomplished,repeated at a succession of yaw positions to form a complete sphericalimage. In some embodiments, a full yaw angle sweep may be performed, andrepeated at a succession of pitch positions to form a complete sphericalimage. Combinations of these two techniques (e.g., partial yaw and pitchsweeps) may also be used.

In some embodiments, moving the image capture medium may further includemaintaining the image capture medium at the orientation substantiallyperpendicular to the non-converging ray for a first portion of thesubstantially circular path, and moving the image capture medium fromthe orientation substantially perpendicular to the non-converging ray tosubstantially perpendicular to the converging ray for a second portionof the substantially circular path (e.g., as shown in FIGS. 2 and 3).

In some embodiments, such as where a plurality of stationary imagecapture media are used to capture imagery, the method 711 at block 729may include locating a plurality of additional image capture media alonga substantially circular path. The plurality of additional image capturemedia may be located so as to include a corresponding plurality oforientations, ranging between an orientation substantially perpendicularto the non-converging ray to an orientation substantially perpendicularto the converging ray.

The method 711 at block 733 may include capturing a portion of aspherical image, such as a monoscopic, stereoscopic, or anomni-stereoscopic image, using a first image capture mediumsubstantially perpendicular to a converging ray originating at a firstviewpoint on an inter-ocular circle, with a convergence angle betweenzero and ninety degrees from a parallel viewpoint baseline position thatincludes a non-converging ray originating at the first viewpoint. Atblock 737, the method 711 may include capturing another portion of theimage, such as an omni-stereoscopic image, using a second image capturemedium substantially perpendicular to a converging ray originating at asecond viewpoint on the inter-ocular circle and having a convergenceangle between zero and ninety degrees from a parallel viewpoint baselineposition that includes a non-converging ray originating at the secondviewpoint. The “first” and “second” image capture media may comprise twoseparate media located at two distinct physical locations, or the samemedium, physically moved through space to occupy two differentlocations.

In some embodiments, the method 711 may include rotating the first imagecapture medium by a selected yaw correction amount about an axisparallel to the converging ray, wherein the selected yaw correctionamount is substantially equal to the convergence angle (or a portion ofthe ultimate extent of the convergence angle, perhaps based on thecurrent pitch position). This may be done to correct image twistdistortion, as described previously, at block 741. The method 711 mayconclude at block 745 with storing one or more portions of an image,such as an omni-stereoscopic image, in a storage medium as one of a pairof triangles included in a convex quadrilateral. As spherical imagecapture operations occur, twist correction may occur prior to, after, orsubstantially simultaneously at the same time as the yaw and pitchmovements used to orient the image capture media during sweepoperations. Of course, if stationary media are used to acquire sphericalimagery, then the twist correction can be subtracted or added to thedesired yaw orientation.

As noted previously, the triangles in each pair may be taken from imageportions seen from a single viewpoint. However, a pair of triangles mayalso represent images taken from different viewpoints, such as where oneor more pairs of triangles includes a first triangle associated with aleft eye view, and a second triangle associated with a right eye view.

Other embodiments may be realized. For example, a method 751 at block769 may include moving the image capture media, or locating a pluralityof capture media, so as to properly orient the media for image capture.In this case, however, the movement or location of the media may bedesigned so as to gravitate the media capture rays (generallyperpendicular to the capture plane of the media) toward the center ofthe inter-ocular circle. For example, the method 751 at block 769 mayinclude moving an image capture medium along the diameter of aninter-ocular circle from a first endpoint (e.g., a first viewpoint) ofthe diameter to a point between the first endpoint and the center of theinter-ocular circle. During this activity, the image capture medium maybe moved nonlinearly along the diameter from the first endpoint to thecenter of the circle along a substantially linear path. In someembodiments, instead of moving the media, or in addition to moving themedia, the method 751 may include locating a plurality of additionalimage capture media along the diameter from the first endpoint to thecenter of the circle. This may occur when a plurality of stationarymedia are used for image capture, for example.

Thus, in some embodiments, the method 751 may include capturing a firstportion of an image, such as a monoscopic, stereoscopic, or anomni-stereoscopic image, using an image capture medium located so as tobe substantially perpendicular to a non-converging ray originating at afirst endpoint of a diameter defining an inter-ocular circle at block773. The method 751 may continue at block 777 with capturing a secondportion of the image, such as an omni-stereoscopic image, using theimage capture medium located so as to be substantially perpendicular toa non-converging ray originating at a point of the diameter between thefirst endpoint and the center of the inter-ocular circle.

In some embodiments, the method 751 may include capturing a plurality ofother portions of the image, such as an omni-stereoscopic image, atblock 781. This image capture may be accomplished using a single capturemedium, physically moved between subsequent image capture locations, ora plurality of stationary image capture media, where image captureoperation is electronically cycled between the individual mediaelements. Thus, the method 751 may include capturing another portion ofthe image, such as an omni-stereoscopic image, using another imagecapture medium substantially perpendicular to a non-converging rayoriginating at a second viewpoint located at a second endpoint of thediameter defining the inter-ocular circle.

In some embodiments (e.g., where stationary capture media image captureis employed), the method 751 may include locating a plurality of otherimage capture media along the diameter from the second endpoint to asecond point of the diameter between the second non-central endpoint andthe center of the inter-ocular circle, and capturing a plurality ofadditional portions of the omni-stereoscopic image using the pluralityof other image capture media. In some embodiments (e.g., where movingcapture media image capture are used), the method 751 may include movingthe other image capture medium along the diameter from the secondendpoint to a second point of the diameter between the second endpointand the center of the inter-ocular circle, and capturing a plurality ofadditional portions of the omni-stereoscopic image. The method 751 mayconclude at block 785 with storing one or more portions of the image ina storage medium as one of a pair of triangles included in a convexquadrilateral.

It should be noted that the methods described herein do not have to beexecuted in the order described, or in any particular order. Moreover,various activities described with respect to the methods identifiedherein can be executed in repetitive, serial, or parallel fashion.Information, including parameters, commands, operands, and other data,can be sent and received in the form of one or more carrier waves.

Upon reading and comprehending the content of this disclosure, one ofordinary skill in the art will understand the manner in which a softwareprogram can be launched from a computer-readable medium in acomputer-based system to execute the functions defined in the softwareprogram. One of ordinary skill in the art will further understand thevarious programming languages that may be employed to create one or moresoftware programs designed to implement and perform the methodsdisclosed herein. The programs may be structured in an object-orientatedformat using an object-oriented language such as Java or C++.Alternatively, the programs can be structured in a procedure-orientatedformat using a procedural language, such as assembly or C. The softwarecomponents may communicate using any of a number of mechanisms wellknown to those skilled in the art, such as application programinterfaces or interprocess communication techniques, including remoteprocedure calls. The teachings of various embodiments are not limited toany particular programming language or environment.

Thus, other embodiments may be realized. For example, FIG. 8 is a blockdiagram of an article 885 according to various embodiments of theinvention. Examples of such embodiments include a computer, a memorysystem, a magnetic or optical disk, some other storage device, and/orany type of electronic device or system. The article 885 may include aprocessor 887 coupled to a machine-accessible medium such as a memory889 (e.g., a memory including an electrical, optical, or electromagneticconductor) having associated information 891 (e.g., computer programinstructions and/or data), which, when accessed, results in a machine(e.g., the processor 887) performing such actions as capturing a portionof a spherical image (e.g., an omni-stereoscopic image) using a firstimage capture medium substantially perpendicular to a converging rayoriginating at a first viewpoint on an inter-ocular circle. Theconverging ray may have a convergence angle between zero and ninetydegrees from a parallel viewpoint baseline position that includes anon-converging ray originating at the first viewpoint.

Further activities may include storing the portion (or a subset of theportion) of the spherical image in a storage medium as one of a pair oftriangles included in a convex quadrilateral, as well as capturinganother portion of the spherical image using a second image capturemedium, which may in turn be located so as to be substantiallyperpendicular to a converging ray originating at a second viewpoint onthe inter-ocular circle, with a convergence angle between zero andninety degrees from a parallel viewpoint baseline position that includesa non-converging ray originating at the second viewpoint.

In some embodiments, the article 885 may include a processor 887 coupledto a machine-accessible medium such as a memory 889 having associatedinformation 891 which, when accessed, results in a machine performingsuch actions as capturing a first portion of a spherical image (e.g., anomni-stereoscopic image) using an image capture medium substantiallyperpendicular to a non-converging ray originating at a first viewpointat a first endpoint of a diameter defining an inter-ocular circle, andcapturing a second portion of the spherical image using another imagecapture medium substantially perpendicular to a non-converging rayoriginating on a first point of the diameter between the first endpointand a center of the inter-ocular circle.

Further actions may include locating a plurality of additional imagecapture media along the diameter from the first endpoint to the firstpoint, and capturing a plurality of other portions of the sphericalimage using the plurality of additional image capture media. Additionalactions may include capturing another portion of the spherical imageusing another image capture medium substantially perpendicular to anon-converging ray originating at a second viewpoint at a secondendpoint of the diameter defining the inter-ocular circle.

Implementing the apparatus, systems, and methods disclosed herein maysignificantly reduce the amount of distortion present in acquired andstored data that is used to display monoscopic and stereoscopicspherical images, especially as viewing directions tend toward theapexes of the spherical imagery.

The accompanying drawings that form a part hereof show by way ofillustration, and not of limitation, specific embodiments in which thesubject matter may be practiced. The embodiments illustrated aredescribed in sufficient detail to enable those skilled in the art topractice the teachings disclosed herein. Other embodiments may beutilized and derived therefrom, such that structural and logicalsubstitutions and changes may be made without departing from the scopeof this disclosure. This Detailed Description, therefore, is not to betaken in a limiting sense, and the scope of various embodiments isdefined only by the appended claims, along with the full range ofequivalents to which such claims are entitled.

Such embodiments of the inventive subject matter may be referred toherein, individually and/or collectively, by the term “invention” merelyfor convenience and without intending to voluntarily limit the scope ofthis application to any single invention or inventive concept if morethan one is in fact disclosed. Thus, although specific embodiments havebeen illustrated and described herein, it should be appreciated that anyarrangement calculated to achieve the same purpose may be substitutedfor the specific embodiments shown. This disclosure is intended to coverany and all adaptations or variations of various embodiments.Combinations of the above embodiments, and other embodiments notspecifically described herein, will be apparent to those of skill in theart upon reviewing the above description.

The Abstract of the Disclosure is provided to comply with 37 C.F.R.§1.72(b), requiring an abstract that will allow the reader to quicklyascertain the nature of the technical disclosure. It is submitted withthe understanding that it will not be used to interpret or limit thescope or meaning of the claims. In addition, in the foregoing DetailedDescription, it can be seen that various features are grouped togetherin a single embodiment for the purpose of streamlining the disclosure.This method of disclosure is not to be interpreted as reflecting anintention that the claimed embodiments require more features than areexpressly recited in each claim. Rather, as the following claimsreflect, inventive subject matter lies in less than all features of asingle disclosed embodiment. Thus the following claims are herebyincorporated into the Detailed Description, with each claim standing onits own as a separate embodiment.

What is claimed is:
 1. An apparatus comprising: a first image-capturemedium located at a first viewpoint; and a second image-capture mediumlocated at a second viewpoint, wherein the first image-capture medium isconfigured to capture a left-eye part of a first portion of astereoscopic spherical image of a first portion of a scene, and to forma first optical axis that extends between the first viewpoint and thefirst portion of the scene, wherein the second image-capture medium isconfigured to capture a right-eye part of the first portion of thestereoscopic spherical image of the first portion of the scene, and toform a second optical axis that extends from the second viewpoint to thefirst portion of the scene, wherein the first optical axis and thesecond optical axis converge toward the first portion of the scene at afirst predetermined convergence angle, and wherein the convergence angleis varied for image-portion capture operations performed at differentpitch angles towards an apex of the scene.
 2. The apparatus of claim 1,wherein the distance between the first viewpoint and the secondviewpoint is predetermined and constant for each of a plurality ofcapture operations.
 3. The apparatus of claim 1, wherein the left-eyepart of the first portion of the stereoscopic spherical image consistsof a single pixel and the right-eye part of the first portion of thestereoscopic spherical image consists of a single pixel.
 4. Theapparatus of claim 1, wherein the apparatus is configured to rotate sothe first image-capture medium is located at a third viewpoint and thesecond image-capture medium is located at a fourth viewpoint, and then:the first image-capture medium captures a left-eye part of a secondportion of the stereoscopic spherical image of a second portion of thescene with the first image-capture medium having a third optical axisthat extends between the third viewpoint and the second portion of thescene, and the second image-capture medium captures a right-eye part ofthe second portion of the stereoscopic spherical image of the secondportion of the scene with the second image-capture medium having afourth optical axis that extends from the fourth viewpoint to the secondportion of the scene, and wherein the third optical axis and the fourthoptical axis converge toward the scene at a second predeterminedconvergence angle that is different from the first predeterminedconvergence angle.
 5. The apparatus of claim 4, wherein the apparatus isconfigured to combine the first and second portions of the capturedstereoscopic spherical image to form a larger continuous portion of thestereoscopic spherical image.
 6. The apparatus of claim 4, wherein theapparatus is configured to iteratively performrotation-and-image-capture operations over a full range ofinter-ocular-circle diameters and to combine resulting portions of thecaptured stereoscopic spherical image to form a complete continuousstereoscopic spherical image.
 7. The apparatus of claim 4, wherein thefirst image-capture medium and the second image-capture medium areconfigured to capture images as the first optical axis and the secondoptical axis point along twist-corrected converging sweep paths towardsthe apex of the scene.
 8. The apparatus of claim 1, wherein theconvergence angle is varied according to a linear-interpolationmathematical formula.
 9. The apparatus of claim 1, wherein theconvergence angle is varied according to an irregular pattern.
 10. Theapparatus of claim 1, wherein a diameter of the inter-ocular circle isvaried at each of a plurality of image-portion capture operations tofurther control the stereoscopic affects achieved.
 11. The apparatus ofclaim 10, wherein the diameter of the inter-ocular circle is variedaccording to a linear-interpolation mathematical formula.
 12. A methodfor capturing a stereoscopic spherical image by capturing each portionof the stereoscopic spherical image, wherein the capturing of eachportion of the stereoscopic spherical image comprises: providing a firstimage-capture medium located at a first viewpoint; providing a secondimage-capture medium located at a second viewpoint; determining aconvergence angle for each of a plurality of portions of thestereoscopic spherical image, wherein the convergence angle varies atdifferent pitch angles towards an apex of a scene for the capturing ofdifferent portions of the stereoscopic spherical image; configuring thefirst image-capture medium to capture a left-eye part of a first portionof the stereoscopic spherical image of a first portion of the scene,such that the first image-capture medium is oriented toward the firstportion of the scene along a first optical axis that extends between thefirst viewpoint and the first portion of the scene; and configuring thesecond image-capture medium to capture a right-eye part of the firstportion of the stereoscopic spherical image of the first portion of thescene, such that the second image-capture medium is oriented toward thefirst portion of the scene along a second optical axis that extendsbetween the second viewpoint and the first portion of the scene, andsuch that the first optical axis and the second optical axis convergetoward the first portion of the scene at the convergence angle for thefirst portion of the stereoscopic spherical image.
 13. The method ofclaim 12, wherein the capture of each portion of the stereoscopicspherical image further comprises: determining a first distance betweenthe first viewpoint and the second viewpoint based, at least in part, ona distance from the portion of the stereoscopic spherical image to anapex of the stereoscopic spherical image.
 14. The method of claim 13,wherein the convergence angle is determined, at least in part, by thedistance from the portion of the stereoscopic spherical image to theapex of the stereoscopic spherical image.
 15. The method of claim 12,wherein the convergence angle is determined, at least in part, by adistance from the portion of the stereoscopic spherical image to an apexof the stereoscopic spherical image.
 16. The method of claim 12, whereinthe left-eye part of the first portion of the stereoscopic sphericalimage consists of a single pixel and the right-eye part of the firstportion of the stereoscopic spherical image consists of a single pixel.17. The method of claim 12, further comprising: combining a plurality ofportions of the stereoscopic spherical image to form a larger continuousportion of the stereoscopic spherical image.
 18. A method for displayinga stereoscopic spherical image captured by capturing each portion of thestereoscopic spherical image, wherein the capturing of each portion ofthe stereoscopic spherical image comprises: providing a firstimage-capture medium located at a first viewpoint; providing a secondimage-capture medium located at a second viewpoint; determining aconvergence angle for each of a plurality of portions of thestereoscopic spherical image, wherein the convergence angle varies atdifferent pitch angles towards an apex of a scene for the capturing ofdifferent portions of the stereoscopic spherical image; configuring thefirst image-capture medium to capture a left-eye part of the portion ofthe stereoscopic spherical image of a first portion of the scene, suchthat the first image-capture medium is oriented toward the first portionof the scene along a first optical axis that extends between the firstviewpoint and the first portion of the scene; and configuring the secondimage-capture medium to capture a right-eye part of the portion of thestereoscopic spherical image, such that the second image-capture mediumis oriented toward the first portion of the scene along a second opticalaxis that extends between the second viewpoint and the first portion ofthe scene, and such that the first optical axis and the second opticalaxis converge at the convergence angle for the first portion of thestereoscopic spherical image; and wherein the displaying of thestereoscopic spherical image comprises: displaying the left-eye part andthe right eye part of the portion of the spherical image as astereoscopic image.
 19. The method of claim 18, wherein the capture ofeach portion of the stereoscopic spherical image further comprises:determining a first distance between the first viewpoint and the secondviewpoint based, at least in part, on a distance from the portion of thestereoscopic spherical image to an apex of the stereoscopic sphericalimage.
 20. The method of claim 19, wherein the convergence angle isdetermined, at least in part, by the distance from the portion of thestereoscopic spherical image to the apex of the stereoscopic sphericalimage.
 21. The method of claim 18, wherein the convergence angle isdetermined, at least in part, by a distance from the portion of thestereoscopic spherical image to an apex of the stereoscopic sphericalimage.
 22. The method of claim 18, wherein the left-eye part of thefirst portion of the stereoscopic spherical image consists of a singlepixel and the right-eye part of the first portion of the stereoscopicspherical image consists of a single pixel.
 23. A method comprising:providing a device having a plurality of image-capture media including afirst image-capture medium and a second image-capture medium, wherein,when the first image-capture medium is located at a first viewpoint andthe second image-capture medium is located at a second viewpoint, then:capturing a left-eye part of a first portion of a stereoscopic sphericalimage of a first portion of a scene with the first image-capture mediumwhen the first image-capture medium has its optical axis extendingbetween the first viewpoint and the first portion of the scene, andcapturing a right-eye part of the first portion of the stereoscopicspherical image of the first portion of the scene with the secondimage-capture medium when the second image-capture medium has itsoptical axis extending from the second viewpoint to the first portion ofthe scene, and wherein the first optical axis and the second opticalaxis converge toward the scene at a predetermined convergence angle, andwherein a distance between the first image-capture medium and the secondimage-capture medium varies at different pitch angles towards an apex ofthe scene for capturing different portions of the scene.
 24. Theapparatus of claim 1, wherein the images are generated by a computer.25. The method of claim 12, further comprising: generating the images bya computer.